Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual é a área do voivodenship com 51 comunas?
 ###Tabelas: CREATE TABLE broadcast (broadcast_id AUTO_INCREMENT PRIMARY KEY, Callsign VARCHAR, City of license VARCHAR, Virtual channel VARCHAR, Digital channel VARCHAR, Network VARCHAR) CREATE TABLE injured_players (injured_players_id AUTO_INCREMENT PRIMARY KEY, Position VARCHAR, Number INT, Name VARCHAR, Class VARCHAR, Injury (Status) VARCHAR, Last Update VARCHAR) CREATE TABLE closed_and_aborted_television_providers (closed_and_aborted_television_providers_id AUTO_INCREMENT PRIMARY KEY, Provider VARCHAR, Years VARCHAR, Free or pay VARCHAR, No. of channels VARCHAR, Colour VARCHAR, Digital VARCHAR, Transmission VARCHAR) CREATE TABLE poland's_voivodeships_1975-98_49_voivodeships (poland's_voivodeships_1975-98_49_voivodeships_id AUTO_INCREMENT PRIMARY KEY, Abbreviation VARCHAR, Voivodeship VARCHAR, Capital VARCHAR, Area km² (1998) VARCHAR, Population (1980) VARCHAR, No. of cities INT, No. of communes INT) CREATE TABLE north_conference (north_conference_id AUTO_INCREMENT PRIMARY KEY, Institution VARCHAR, Location VARCHAR, Founded INT, Affiliation VARCHAR, Nickname VARCHAR)  
SELECT Area km² (1998) FROM poland's_voivodeships_1975-98_49_voivodeships WHERE No. of communes = 51